47 lines
1.3 KiB
Go
47 lines
1.3 KiB
Go
// Package strictyaml provides a strict YAML unmarshaller based on `go-yaml/yaml`
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package strictyaml
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import (
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"bytes"
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"errors"
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"fmt"
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"io"
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"gopkg.in/yaml.v3"
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)
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// Unmarshal takes a byte array and an interface passed by reference. The
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// d.Decode will read the next YAML-encoded value from its input and store it in
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// the value pointed to by yamlObj. Any config keys from the incoming YAML
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// document which do not correspond to expected keys in the config struct will
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// result in errors.
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//
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// TODO(https://github.com/go-yaml/yaml/issues/639): Replace this function with
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// yaml.Unmarshal once a more ergonomic way to set unmarshal options is added
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// upstream.
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func Unmarshal(b []byte, yamlObj interface{}) error {
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r := bytes.NewReader(b)
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d := yaml.NewDecoder(r)
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d.KnownFields(true)
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// d.Decode will mutate yamlObj
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err := d.Decode(yamlObj)
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if err != nil {
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// io.EOF is returned when the YAML document is empty.
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if errors.Is(err, io.EOF) {
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return fmt.Errorf("unmarshalling YAML, bytes cannot be nil: %w", err)
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}
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return fmt.Errorf("unmarshalling YAML: %w", err)
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}
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// As bytes are read by the decoder, the length of the byte buffer should
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// decrease. If it doesn't, there's a problem.
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if r.Len() != 0 {
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return fmt.Errorf("yaml object of size %d bytes had %d bytes of unexpected unconsumed trailers", r.Size(), r.Len())
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}
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return nil
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}
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